The present invention relates to levelers, a device typically attached to tractors, excavators, and skid-steer vehicles for the purpose of levelling and smoothing the ground. It is envisaged however that the present invention may find other uses, and be adapted therefore.
Levelers take many shapes and designs, including those which are merely dragged along the ground. Many, however, have blades (sometimes known as mould boards) for levelling and altering the contour of the ground. In these versions, the height of the blade is typically able to be altered, which allows the user control over grading, levelling and/or sculpting the contour of the ground. Elevation adjustment is sometimes achieved by raising the entire levelling assembly, while others may rely on merely raising and lowering the portion with the blade. One prior art device uses a central hydraulic actuator to raise and lower the blade portion, which is connected to the main body portion with two dual parallel arm linkages. A wheeled carriage extending from the main body portion helps keep the main body portion at a constant height relative to the ground.
For agricultural applications, generally the contour of the land needs merely to be smoothed. However, levelers have found use in construction sites where they are commonly used to level large areas for foundations, particularly concrete foundations. Here the levelling needs to be precisely, and truly horizontal. Achieving this requires operator skill, and patience. Wheeled versions, such as described above, tend to be most popular as merely raising and lowering the blade (as opposed to the entire leveler assembly) is quicker and more precise, enabling quick responses. When coupled with a laser levelling system, adjusting only the blade elevation allows the operator to work much more quickly.
In many instances, not only must the blade elevation be altered but so too must its inclination relative to the tractor/skid steer to ensure that it is always at true horizontal. If the tractor unit traverses a slope, a fixed inclination blade will level the ground at the same inclination as the tractor unit is. This makes levelling mounds and slopes to the true horizontal extremely difficult.
To address this the prior art uses leveler attachment arrangements (typically the ubiquitous Quick-Hitch) which include an arrangement for varying the inclination of the attachment. These rotational arrangements are expensive, and also add considerable weight to the load carried by the tractor unit. They are also limited in the degree of precision with respect to inclination to a particular angle, and relatively slow to adjust. This slows any levelling operation.
Accordingly, the inventor has identified a need for a levelling unit, which can address the above issues, and at least provide a blade portion able to be adjusted in elevation, and inclination (about a rotational axis substantially the same as the direction of travel), and which can be attached to standard connections such as the Quick Hitch, while avoiding the use of additional rotational assemblies.
Ideally also, it would allow a degree of precision making it suitable for use in construction sites, and particularly for foundations. Ideally also, it would speed the work of the user in levelling ground of different inclinations and contours.
Further, it would be desirable to have an adjustable blade device attachable to an excavator, whose arms do not provide for rotation of a blade about an axis perpendicular to the general plane of the blade. Attempting to use a standard tilt adjustable hitch as well as the levelling assembly tends to add too much weight to the end of the excavator arm, and limits its usefulness—especially on smaller excavators able to operate in tight confines. Hence the use of blades on excavators, while desirable and useful, has been hindered and limited.
It would therefore be desirable and useful to provide a potential solution allowing levelling assemblies to be used on excavators.
It would also be useful to provide an improved mounting system which could allow attachment to a levelling assembly to the existing blade or bucket of a vehicle.
It is an object of the present invention to address at least some of the above problems.
At the very least it is an object of the present invention to provide the public with a useful alternative choice.
Aspects of the present invention will be described by way of example only and with reference to the ensuing description.